Magnesium

Magnesium: Overview

Magnesium is an important mineral that helps improve stamina, endurance, vitality, and energy levels. Magnesium is involved in several hundred enzymatic reactions, being required for cardiovascular function and the conversion of carbohydrates, proteins and fats to energy. It also functions in muscle relaxation and contraction, nerve transmissions, and the removal of excess toxic substances from the body. Magnesium is one of the most abundant minerals in the soft tissues.

Magnesium is the "iron" of the plant world – as iron is to hemoglobin, so magnesium is to chlorophyll, the "blood" pigment of plants. The central atom of the chlorophyll structure is magnesium.

About 65% of our magnesium is contained in the bones and teeth. As with calcium, the bones act as a reservoir for magnesium in times of need. Elsewhere, most of it, like potassium, is found inside the cells. Usually, about 40-50% of the magnesium we consume is absorbed, though this may vary from 25-75% depending on stomach acid levels, body needs, type of magnesium, and dietary habits. The kidneys can excrete or conserve magnesium according to body needs. The intestines can also eliminate excess magnesium in the feces.

Magnesium has many essential metabolic functions in the body. It is important in the production and transfer of energy, in muscle contraction and relaxation, in nerve conduction, in protein synthesis, and in many biochemical reactions as a cofactor to enzymes. Magnesium also dilates blood vessels.

One of the most abundant elements on the earth, Magnesium makes up more than 2% of the earth's weight. As a dietary mineral, it would be hard to overestimate the importance and need for Magnesium. Magnesium is required in well over 300 different enzymatic reactions including most ATP-driven reactions. Magnesium is critical to the proper use and maintenance of calcium. In fact, many individuals with "calcium deficiency" are not deficient in calcium at all, but instead are magnesium deficient; leading to improper use of calcium.

Source

Green vegetables, especially dark greens such as spinach, provide magnesium because the center of the chlorophyll molecule contains magnesium. Nuts, seeds, and some whole grains are also good sources of magnesium.

Although magnesium is present in many foods, it usually occurs in small amounts. As with most nutrients, daily needs for magnesium cannot be met from a single food. Eating a wide variety of foods, including five servings of fruits and vegetables daily and plenty of whole grains, helps to ensure an adequate intake of magnesium.

The magnesium content of refined foods is usually low. Whole-wheat bread, for example, has twice as much magnesium as white bread because the magnesium-rich germ and bran are removed when white flour is processed.

Almost all dietary magnesium comes from the vegetable kingdom, though seafood has fairly high amounts. Beet leaves are an excellent source; most nuts, seeds and legumes have high amounts of magnesium; soy products, especially soy flour and tofu, and nuts such as almonds, pecans, cashews, and brazils are good examples. The whole grains, particularly wheat (especially the bran and germ), millet, and brown rice, and fruits such as avocado and dried apricot are other sources. Hard water can also be a valuable source of magnesium.

Magnesium Ascorbate: A salt form of magnesium with the anion ascorbate. Typically contains about 20% magnesium by weight. Used when a vitamin C claim is also intended with the product.

Magnesium Aspartate: A salt form of magnesium with the anion from aspartic acid (aspartate). Typically contains between 20 and 22% magnesium by weight.

Magnesium Carbonate: A carbonate salt of magnesium yielding approximately 25% magnesium as magnesium oxide. Used primarily as an antacid, buffering, or laxative additive rather than a source of magnesium.

Magnesium Citrate: Yet another salt form of magnesium with the anion from citric acid (citrate). This salt form yields about 16% magnesium.

Magnesium Oxide: A form of magnesium tightly bonded (ionic) with oxygen. Often called magnesia. Contains 60% magnesium. While high in magnesium, this is one of the poorest forms of magnesium supplementation. This form is useful in high doses as an antacid (see Mg Carbonate) or a laxative. Many manufacturers cut corners to use magnesium oxide because the cost and less material is required to meet the USRDA compared to the better sources with less magnesium by weight.

Magnesium Stearate: A salt form of magnesium with two molecules of stearic acid (18 carbon fatty acid). Used almost exclusively as a lubricant in the formation of tablets and capsules. Amounts are usually too low to account for any beneficial magnesium. Suggestions about the negative aspects of using magnesium stearate have been greatly exaggerated. Magnesium stearate should be food grade or better, and from a vegetable source. Magnesium stearate is listed in the National Formulary (NF).

Function; Why it is Recommended

One of the most powerful antioxidants for your heart and circulatory system, magnesium is important for proper nerve, lung and cardiac function. It has been shown to be capable of lowering blood pressure.

Individuals with chronically low blood levels of potassium and calcium may have an underlying problem with magnesium deficiency. Adding magnesium supplements to their diets may make potassium and calcium supplementation more effective for them. Doctors routinely evaluate magnesium status when potassium and calcium levels are abnormal, and prescribe a magnesium supplement when indicated.

Magnesium can be lost through the consumption of saturated fats, soft drinks, and excessive amounts of alcoholic beverages. Intake of diuretics is another major cause of loss.

A magnesium deficiency has been linked with cardiovascular disease. Capable of preventing arrhythmias (heart beat irregularity), magnesium has been shown to cut platelet aggregation (blood stickiness) and avert spasm of the coronary arteries. It also improves the metabolic efficiency of the myocardium (heart muscle) and reduces angina when other measures fail. "In chelation therapy magnesium helps the coronary arteries to relax and open up so that a greater amount of blood can flow through them", writes Dr. Morton Walker in the Chelation Way.

Instructions

The current RDA is about 350mg for men and 300mg for women, increasing to about 450mg during pregnancy and lactation. Many authorities feel that the RDA should be doubled, to about 600-700mg. An average diet usually supplies about 120mg of magnesium per 1,000 calories, resulting in an estimated daily intake of about 250mg. Unless absorption is great, that is not going to produce adequate tissue levels of magnesium for most people. If you develop muscle cramps when taking magnesium, you may need to increase your level of calcium.

RDA under various stages of life:

Stage of life

RDA (mg/day)

Infant

40-60

Child (ages 1-10)

80-170

Adult

270-400

Pregnancy

320

Lactation

280

The calcium-magnesium balance is important. Magnesium and calcium have similar functions and can either encourage or antagonize each other. The role of these two minerals in muscle contraction is complementary: calcium stimulates muscles and magnesium relaxes them. Our body needs twice as much calcium as magnesium. Consumption of excessive amounts of magnesium inhibits bone formation, whereas excessive consumption of calcium produces symptoms that resemble magnesium deficiency.

To function optimally, magnesium must be balanced in the body with calcium, phosphorus, potassium, and sodium chloride. If calcium intake is increased, magnesium should be increased also. Your doctor may alter this ratio, increasing your level of magnesium for a period of time. Toxicity due to magnesium overload is almost unknown in a nutritional context, as excesses are usually eliminated in the urine and feces. However, symptoms of magnesium toxicity are more likely if calcium intake is low.

The levels of magnesium used by nutritional physicians are commonly in the range of 600-1,000mg. Some calcium-magnesium combinations are formulated with hydrochloric acid and vitamin D to aid mineral absorption. Taking them before bedtime may be very helpful in increasing utilization of both these important minerals and lead to better sleep.

There are conflicting recommendations about the best way to take calcium supplements. The National Institutes of Health (NIH) consensus statement on optimal calcium intake recommends taking no more than 200mg doses, between meals. The recently published clinical guidelines for the prevention and treatment of osteoporosis from the American Association of Clinical Endocrinologists suggest taking supplemental calcium with meals and with a bedtime snack. The decision to take the supplements with or between meals may be based on the type of supplement you're taking. Calcium and magnesium carbonate or hydroxide is more difficult to absorb on an empty stomach or in conditions where there is limited stomach acid. Therefore, absorption may be improved when it's taken with food, especially acidic foods such as citrus juice or fruit. Calcium and magnesium can act as acid neutralizers.

The citrate form is better absorbed on an empty stomach because it does not require gastric acid for absorption. It is the preferred supplement for those lacking stomach acid, including older people, those who have had stomach surgery and those taking medications that block gastric acid production.

The type and amount of calcium and magnesium you take as a supplement should be based on your medical history and your average dietary intake of calcium. Supplements should be taken in smaller doses throughout the day if convenient. If you take an iron supplement, don't take it at the same time as your calcium or magnesium supplement if they are in an antacid form.

A magnesium deficiency can produce electrical changes in the heart muscle and thus lead to arrhythmia. Magnesium is commonly given to patients with arrhythmias but is thought to drive potassium into cells, producing lower serum potassium if not enough potassium is available to maintain normal serum levels. When in doubt, it is best to supplement both potassium and magnesium together.

Magnesium has a mild effect on lowering blood pressure and so is used to treat and prevent hypertension and its effects. In a double-blind, placebo-controlled trial, it was demonstrated that oral magnesium resulted in a significant dose-dependent reduction of systolic and diastolic blood pressure. A mean reduction of 6mm Hg in diastolic pressure in patients with hypertension results in approximately 10% lower risk of coronary artery disease, and a 40% reduction in risk of strokes.

When magnesium levels are low, more calcium flows into the vascular muscle cells, which contracts them – leading to tighter vessels and higher blood pressure. Adequate magnesium levels prevent this.

Dental / Oral

Until further research is done, the best strategy may involve taking the following on a daily basis: magnesium, calcium and pantothenic acid. If bruxism subsides, it is advisable to continue taking these supplements, but perhaps at a lower dosage. If no improvement is observed after 2 months, another approach should be tried.

Environment / Toxicity

Female-Specific

Magnesium has been used specifically to lower blood pressure in pregnant women with preeclampsia, and as a mild anticonvulsant in cases where the condition progresses to eclampsia.

The backbone of management continues to be parenteral (intravenous) administration of magnesium sulfate and delivery as soon as the fetus is mature or when maternal risks outweigh any risks to the fetus. The main purpose of this therapy is to inhibit progression to eclampsia. Magnesium may be given intramuscularly or intravenously.

Menstrual cramps, irritability, fatigue, depression and water retention have been lessened by taking supplemental magnesium, usually given along with calcium and often with vitamin B6. Magnesium is often at its lowest level during menstruation, and many symptoms of premenstrual syndrome (PMS) are relieved when this mineral is replenished. Supplementing magnesium in the same amount (or more) as calcium (about 500-1,000mg daily) is currently recommended for premenstrual problems.

A 1998 study in The Journal of Women's Health found that 200mg a day of magnesium reduced PMS fluid retention, breast tenderness and bloating by 40%. Magnesium is important to regulate muscle relaxation, blood sugar, and to promote sound sleep – all particularly important during PMS.

A deficiency in magnesium causes hyperplasia of the adrenal cortex, elevated aldosterone levels, and increased extracellular fluid volume. Aldosterone increases the urinary excretion of magnesium; hence, a positive feedback mechanism results, which is aggravated since there is no renal mechanism for conserving magnesium.

In laboratory animals, a pyridoxine deficiency at the renal level decreases the kidneys' ability to secrete sodium. In addition, since pyridoxine requires magnesium for phosphorylation to its active form, a magnesium deficiency can lead to decreased B6 activity. Increased insulin secretion, in response to sugar consumption, results in sodium retention that is independent of aldosterone.

In initial research, the supplementation of magnesium has resulted in the satisfying of chocolate cravings. Since both chocolate and cocoa powder contain high levels of magnesium (520mg/100gm and 100mg/100gm, respectively), your craving of chocolate may just reflect your desire to supplement this essential element. Additionally, there are links between low magnesium levels and the development of PMS symptoms, which may explain some women's monthly chocolate binge.

Lead blocks the binding of estrogen to receptor sites and but has no effect on progesterone. A chronic magnesium deficiency may be a contributing factor as it results in increased lead absorption and retention, while decreasing resistance to stress. Hair mineral analysis has shown that, in general, PMS patients have higher heavy metal levels and lower magnesium levels than non-PMS controls. Menstrual cramps, irritability, fatigue, depression and water retention have been lessened with magnesium, usually given along with calcium and often with vitamin B6. Magnesium is often at its lowest level during menstruation. Supplementing magnesium in the same amount (or more) as calcium (about 500-1,000mg daily) is currently recommended for premenstrual problems.

A small study of infertile women and women with a history of miscarriage suggests that low levels of magnesium may impair reproductive function, and may contribute to miscarriage. Oxidation, a process that is damaging to cell membranes, can lead to loss of magnesium. The same study suggests that the antioxidantselenium protects the cell membrane, thereby maintaining appropriate levels of magnesium. The authors of the study suggest taking both magnesium and selenium supplements.

Women who have miscarried have lower levels of selenium than women who carry a pregnancy to full term. Although the authors of the above-mentioned study do not specify the exact amount to take, the recommended doses are generally 300 to 400mg per day of magnesium and 200mcg per day of selenium.

Lab Values

Mental

Several researchers have provided substantial links between low magnesium levels and both migraine and tension headaches, based on both theory and clinical observations. A magnesium deficiency is known to set the stage for the events that can cause a migraine attack or a tension headache. Low brain and tissue magnesium concentrations have been found in patients prone to migraines, indicating a need for supplementation. One of magnesium's key functions is to maintain the tone of the blood vessels.

People who suffer from cluster headaches often have low blood levels of magnesium, and preliminary trials show that intravenous magnesium injections may relieve a cluster headache episode. Magnesium is a relaxant of smooth muscles. [Headache 1995;35: pp.597-600, 1996;36: pp.154-60]

300 young healthy male military recruits undergoing two months of basic training were studied. The trainees were repeatedly exposed to high levels of impulse noises, with ringing of the ears as a consequence. Each recruit received daily either 167mg of magnesium aspartate or a placebo. Permanent hearing loss was significantly more frequent and more severe in the placebo group than in the magnesium group. [Am J Otolaryngol 1994;15: pp.26-32]

Because of its nerve and muscle support, magnesium may also be helpful for nervousness and anxiety. Magnesium is considered the "antistress" mineral. It is a natural tranquilizer as it functions to relax skeletal muscles as well as the smooth muscles of blood vessels and the gastrointestinal tract. Whereas calcium stimulates muscle contraction, magnesium relaxes them.

Musculo-Skeletal

You can reverse bone loss and regain bone mass with calcium, magnesium, vitamin D, and vitamin K. Minimum doses should be in the following ranges: calcium (1200mg), magnesium (400-800mg) vitamin D (400 IU – consider supplementing in the winter months in females), and vitamin K (80mcg). Calcium comes in many forms, so use those which are more absorbable such as hydroxyapatite, citrate, gluconate, and others. Some special preparations have been shown to increase bone density without the use of any other nutrients.

Nutrients

Organ Health

By increasing calcium solubility (especially in the urine) and reducing calcium absorption, magnesium can help prevent kidney stones, especially those composed of calcium oxalate. Research has shown this effect in a high percentage of people who form kidney stones regularly. It is thought that calcium oxalate stones are most likely to form in people who are magnesium deficient, so it may just be correcting that deficiency.

If you have kidney problems, taking magnesium supplements may make you accumulate the mineral too quickly, which could be toxic. In this case you should check with your doctor before taking magnesium supplements.

Respiratory

Magnesium levels are frequently low in asthmatics. [J Lab Clin Med 1940;26: pp.340-4] Current evidence suggests that high dietary magnesium intake may be associated with better lung function and reduced bronchial reactivity. Intravenous injection of magnesium has been reported in most, but not all, double-blind trials to rapidly halt acute asthma attacks.

Magnesium supplements may reduce the bronchoconstriction in asthma by relaxing the muscle around the bronchial tubes. Intravenous solutions containing magnesium and other nutrients have been used successfully to break acute asthma attacks. Oral use improves breathing in asthmatics and the improvement correlates with serum magnesium levels.

In a preliminary trial, 18 adults with asthma took 300mg of magnesium per day for 30 days and experienced decreased bronchial reactivity. [Magnesium-Bulletin 1997;19: pp.4-6] However, a double-blind trial investigated the effects of 400mg per day for three weeks and found a significant improvement in symptoms, but not in objective measures of airflow or airway reactivity. [Eur Respir J 1997;10: pp.2225-9] The amount of magnesium used in these trials was 300 to 400mg per day (children take proportionately less based on their body weight).

Skin-Hair-Nails

Take magnesium supplements or augment your diet with food sources high in this important mineral. Between 200-500mg of magnesium daily has been recommended. You will have to try different doses until you get the amount that is right for your body. See the links between Body Odor and Vitamin B-Complex / Zinc.

Because of its nerve and muscle support, magnesium may also be helpful for muscle cramps. Some people taking magnesium may get relief from leg cramps right away, but a long-standing deficiency can take weeks to overcome with supplements.

Your body is a highly complex, interconnected system. Instead of guessing at what might be wrong, let us help you discover what is really going on inside your body based on the many clues it is giving.